This invention relates to a connection assembly for connecting a chamber assembly of a wafer manufacturing system to a stationary surface. More particularly, this invention relates to a connection assembly for connecting a part of a stage assembly positioned inside the chamber assembly, which provides a controlled atmospheric condition therein, from the external atmospheric condition. The chamber assembly may be a part of a projection exposure apparatus for use in a photolithography process to manufacture semiconductor substrates.
In manufacturing integrated circuits using a photolithography process, light is transmitted through non-opaque portions of a pattern on a reticle, or photomask, through a projection exposure apparatus, and onto a wafer of specially-coated silicon or other semiconductor material. The uncovered portions of the coating, that are exposed to light, are cured. The uncured portions of the coating are removed by an acid bath. Then, the layer of uncovered silicon is altered to produce one layer of the multi-layered integrated circuit. Conventional systems use visible and ultraviolet light for this process. Recently, however, visible and ultraviolet light have been replaced with electron, x-ray, and laser beams, which permit smaller and more intricate patterns.
As the miniaturization of a circuit pattern progresses, the focus depth of the projection exposure apparatus becomes very small, making it difficult to align accurately the overlay of circuit patterns of the multi-layered integrated circuit. As a result, a primary consideration for an overall design of the photolithography system includes building components of the system that achieve precision by maintaining small tolerances. Any vibration, distortion, or misalignment caused by internal, external or environmental disturbances must be kept at minimum. When these disturbances affect an individual part, the focusing properties of the photolithography system are collectively altered.
In a conventional exposure apparatus of a photolithography system to manufacture semiconductor wafers, a wafer stage assembly is used in combination with a projection lens assembly. The wafer stage assembly includes a wafer table to support the wafer substrates, a wafer stage to position the wafer substrates on the wafer table as the wafer stage is being accelerated by a force generated in response to a wafer manufacturing control system, and a wafer stage base to support the wafer stage. The wafer manufacturing control system is a central computerized control system.
The exposure apparatus generally includes an apparatus frame that rigidly supports the wafer stage assembly, the projection lens assembly, a reticle stage assembly, and an illumination system. In operation, the exposure apparatus transfers a pattern of an integrated circuit from a reticle onto the wafer substrates. To permit smaller and more intricate circuit pattern, the projection lens assembly must accurately focus the energy beam on a targeted exposure point of the wafer substrate to align the overlay of circuit patterns of the multi-layered integrated circuit. The exposure apparatus can be mounted to a base, such as the ground or via a vibration isolation system.
There are several different types of photolithography devices, including, for example, a scanning type and a step-and-repeat type. In the scanning type photolithography system, the illumination system exposes the pattern from the reticle onto the wafer with the reticle and the wafer moving synchronously. The reticle stage moves the reticle in a plane generally perpendicular to the optical axis of the lens assembly, while the wafer stage moves the wafer in another plane generally perpendicular to the optical axis of the lens assembly. Scanning of the reticle and wafer occurs while the reticle and wafer are moving synchronously.
Alternatively, in the step-and-repeat type photolithography system, the illumination system exposes the reticle while the reticle and the wafer are stationary. The wafer is in a constant position relative to the reticle and the lens assembly during the exposure of an individual field. Between consecutive exposure steps, the wafer is moved by the wafer stage perpendicular to the optical axis of the lens assembly so that the next field of the wafer is brought into position relative to the lens assembly and the reticle for exposure. Using this process, the images on the reticle are sequentially exposed onto the fields of the wafer.
In most types of photolithography systems, the photolithography process of the conventional exposure apparatus is performed with the semiconductor substrates exposed to the atmosphere.
Recent developments, enabling the photolithography process to meet certain wafer manufacturing specifications and to improve the quality of the resulting wafers, require that the semiconductor substrates be processed in a controlled atmosphere, such as nitrogen or helium. To take advantage of the recent developments, a wafer stage chamber assembly has been proposed that isolates the semiconductor substrates, the wafer stage device, and the manufacturing process thereof from the atmosphere. The wafer stage chamber assembly is discussed in further detail in U.S. patent application Ser. No. 09/759,218 (attorney reference no. 7303.0034, PAO 358-US), filed on Jan. 16, 2001 the entire disclosure of which is incorporated by reference.
Occasionally, the wafer stage chamber assembly needs to be disassembled by removing a part or parts from the exposure apparatus for servicing purposes, periodic maintenance, or other reasons. Since some parts of the wafer stage assembly in the chamber assembly are connected to a stationary surface, such as the ground, there is a need for a quick way to disconnect the parts from the stationary surface. The present invention is directed to a connection assembly for connecting the parts inside the wafer stage chamber assembly to a stationary surface, the connection assembly being capable of maintaining the controlled condition inside the wafer stage chamber assembly while allowing a quick way to disconnect the parts when the chamber assembly needs to be removed for maintenance or servicing.
The advantages and purposes of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purposes of the invention will be realized and attained by the elements and combinations particularly pointed out in the appended claims.
To attain the advantages and consistent with the principles of the invention, as embodied and broadly described herein, a first aspect of the invention is a connection assembly of a chamber assembly, comprising a vibration isolation connection assembly and a bellows assembly. The vibration isolation connection assembly is removably connected to a part positioned in the chamber assembly via a link. The bellows assembly encases the vibration isolation connection assembly to maintain a controlled condition of the chamber assembly. The bellows assembly has a first end removably connected to a panel of the chamber assembly, and a second end removably connected to a stationary surface. The bellows assembly is compressible to expose the vibration isolation connection assembly.
A second aspect of the present invention is a vibration isolation connection assembly to connect a part in a chamber assembly to a stationary surface. The vibration isolation connection assembly comprises a shock absorbing assembly and a shock absorbing nut. The shock absorbing assembly has a first end for a removable first mating engagement with a link, and a second end removably connected to the stationary surface. The link connects the shock absorbing assembly to the part in the chamber assembly. The shock absorbing nut is positioned adjacent to the first end of the shock absorbing assembly to engage with the link.
A third aspect of the present invention is a bellows assembly to encase an assembly connecting a chamber assembly to a stationary surface. The chamber assembly provides a controlled atmospheric condition therein. The bellows assembly comprises a bellows cylinder having a first end removably connected to a panel of the chamber assembly, and a second end removably connected to the stationary surface. The bellows assembly also comprises a bellows attached to the bellows cylinder.
A fourth aspect of the present invention is a method for connecting a part in a chamber assembly to a stationary surface. The chamber assembly provides a controlled atmospheric condition therein. The method comprises connecting the part in the chamber assembly via a link to a vibration isolation connection assembly, and encasing the vibration isolation connection assembly to maintain the controlled atmospheric condition of the chamber assembly.
A fifth aspect of the present invention is a method for connecting a reaction frame in a chamber assembly to a stationary surface. The method comprises providing a bellows assembly to removably connect the chamber assembly to the stationary surface. The bellows assembly has a sealing engagement to maintain a controlled condition of the chamber assembly. The method also comprises providing a vibration isolation connection assembly to removably connect a frame positioned in the chamber assembly to a shock absorbing assembly.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. Additional advantages will be set forth in the description which follows, and in part will be understood from the description, or may be learned by practice of the invention. The advantages and purposes may be obtained by means of the combinations set forth in the attached claims.